Lifting-jack.



UNITED STATES PATENT OFFICE.

ROBERT S. NOAH, OF ANNAPOLIS, MARYLAND, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, ONE-THIRD '10 ANDREW H. WILSON, ONE-THIRD'TO JOHN F. MARTIN, AND ONE-THIRD TO GEORGE L. CARSON, ALL OF ANNA'POLIS, MARY- LAND.

LIFTING-J'AGK.

Specification of Letters Patent.

Patented May 22, 1917.

Application filed February 23, 1916. Serial No. 79,825.

ing-Jacks, of which the following is a specifieation.

This invention relates to lifting devices which are characterized by a traveling bar adapted to engage the load or object to be lifted, and the invention has for its object to provide a novel and improved means for actuating said liftin bar. 7

The object stated is attained by means of a combination and arrangement of parts to be hereinafter described and claimed, and in order that the. same may be better under.- stood, reference is had to the accompanying drawing forming a part of this specification.

In the drawing, Figure 1 is a side elevation of the device, and Fig. 2 is a similar view, partly broken away and in section.

Referring specifically to the drawing, 5 denotes an upright guide standard rising from a base 6, and being hollow, as indicated'at 7, to accommodate the lifting bar of the device, the latter comprising two telescopically connected sections 8 and 9, respectively. The section 8 is hollow to accommodate the section 9, and the latter has at its upper end a head or seat 10 to engage the object or load to be lifted. 'The'head 10 also carries a depending hook bar 11 designed to be used when the object'is close to the ground, the hook being placedunder I the object. The two lifting bar sections are locked in adjusted position relative to each other by a cross pin 12 inserted through one of a series of apertures 13 in the section 9. Any, othersuitable means may be provided for this purpose. The cross pin is carried by a chain 14 connected to the section 8.

The following means are provided. for operating the lifting bar composed of the sections 8 and 9:

On one side of the lifting bar section 8 is a rack 15 with which meshes a pinion 16 *mounted on a shaft 17 carried by two laterall spaced bearing extensions 18 ofthe stan ard 5, the pinion being located between said parts 18, and the face of the standard having an openin through which the pinion extends into mes with the rack. The pinion is operated by a hand lever 19 fulcrumed at one end on the shaft 17, this end of the lever being forked to straddle the pinion, the twobranches of the fork being indicated at 20. The fork branches have alined apertures 21 through which the shaft passes.

' Between the fork branches 20, at the inner ends thereof, the lever 19 has a rigidly fixed means, hook 22, designed to engage the teeth 23 of the pinion 16 for rotating the latter. This part of the lever also has two recesses 24 to accommodate the pinion teeth when the lever is swung as will be presently described. The teeth 23 are unlike ordinary gear teeth, they being hook-shaped, so that the hook 22 may obtain a good hold.

Theapertures 21 of the lever 19 are elongated in the direction of the length of the lever, so that the latter may be moved in the direction of its length to engage its hook 22 with the pinion teeth 23, and also to disengage the same as will be presently described.

Loosely seating in recesses in the top edges of the parts 18, and straddling the same, is a pawl in the form of a cross pin 25, the .same being carried by springs 26 attached to the standard 5. The pawl is so positioned that it seats in the space between two adjacent pinion teeth 23, and its function is to lock the pinion a ainst turning in a direction to lowerthe li ing bar.

In operation, to elevate the liftin bar, the lever 19 is swung upward and shi ed in the direction of its length to engage the hook 22 with one of the pinion teeth 23 as shown dotted inFig. 2. The lever is now swung down, and as it is coupled to the pinion, the latter turns in a direction to elevate the lifting bar through the rack 15. For the next stroke, the lever is shifted to disengage its hook from the pinion tooth, and it is then, again shifted to obtain anew hold, after which the lever is swung down to turn the pinion as before. These operations are repeated until the object has been elevated to the desired height. When the "lever is disconnected from the pinion preparatory for a new stroke, the pawl 25 locks the pinion and prevents the lifting bar from dropping down.

cient length to permit 'the lever to be moved forward far enough to place the forked end under the pawl. The lever hook must also be engaged with one of the pinion teeth as before to couple the lever to the pinion, in order that the descent of the lifting bar may be checked and controlled. The pawl is disengaged from the pinion by a downward swing of the lever. The recesses 24 enable the lever to be swung relative to the pinion a suflicient distance to effect disengagement of the pawl.

I claim:

In a lifting jack, a lifting bar provided with a rack on one side, a support having spaced extensions provided with recesses in their top edges, a pinion mounted between said extensions in mesh wlth said rack, a

cross-pin normally seated in said recesses of the support extensions and extending from one to the other in the path of-the pinion teeth to prevent the turning of the pinion in one direction, and a longitudinally adjustable lever formed with two separate rigid means one of which is adapted to engage said crosspin to release it from engagement with the pinion, and the other being adapted to engage said pinion to raise and lower said lifting bar.

In testimony whereof I aflix my signature in presence of two witnesses.

ROBERTS. NOAH.

Witnesses:

E, WALTON BREWINGTON, HOWARD D. ADAMS. 

